package com.itheima.reggie.filter;

import com.alibaba.fastjson.JSON;
import com.itheima.reggie.common.BaseContext;
import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经完成登录
 */
@Slf4j
@WebFilter(filterName = "loginCheckFilter", asyncSupported = true, urlPatterns = "/*" )
public class LoginCheckFilter implements Filter {
    //路径匹配器，支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        long id = Thread.currentThread().getId();
//        log.info("线程id为：{}",id);

        // 1.获取本次请求的URI
        // 特别注意这里要清理浏览器的缓存，不然结果可能和想的不一样
        String requestURI = request.getRequestURI(); //  /backend/index.html


        log.info("拦截到请求: {}", requestURI);

        // 定义不需要处理的请求路径(即不需要拦截的资源)
        String[] urls = new String[]{
                "/employee/login",
                "/employee/logout",
                "/backend/**",          // /backend/index.html 匹配到了, 被放行了, 但是/employee/page被拦截了
                "/front/**",
                "/common/**",
                "/user/sendMsg",
                "/user/login"

        };

        // 2.判定本次请求是否需要处理
        boolean check = check(urls, requestURI);

        // 3.如果不需要处理直接放行
        if (check) {
            log.info("本次请求{}不需要处理", requestURI);
            filterChain.doFilter(request, response);
            return;
        }

        // 后台
        // 4-1.判断登录状态，如果已经登录，则直接放行
        if (request.getSession().getAttribute("employee") != null) {
            log.info("用户已登录，用户id为: {}", request.getSession().getAttribute("employee"));

            // 如果用户登录成功，则创建线程，并且把用户id保存在当前线程中，线程名即为当前用户名，以便用户进行更新时信息填充
            Long empId = (Long) request.getSession().getAttribute("employee");
            BaseContext.setCurrentId(empId);

            filterChain.doFilter(request, response);
            return;
        }

        // 前台
        // 4-2.判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("user") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("user"));

            Long userId = (Long) request.getSession().getAttribute("user");
            BaseContext.setCurrentId(userId);

            filterChain.doFilter(request,response);
            return;
        }

        // 5.如果用户没有登录则返回登录结果，通过输出流方式向客户端页面响应数据
        log.info("用户没有登录");
        response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
        return;
    }

    /**
     * 路径匹配，检查本次请求是否需要放行
     *
     * @param urls       需要放行的路径集合
     * @param requestURI 请求路径
     * @return 是否放行
     */
    private boolean check(String[] urls, String requestURI) {
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if (match) {
                return true;
            }
        }
        return false;
    }
}
